Linkup vs SerpApi

Linkup

Per-call prices from $0.005, and no credit taken for errors, missing parameters or empty results. 429 covers both exhausted credit and rate limiting, with no Retry-After.

SerpApi

Over 100 engines behind one GET URL, with json_restrictor field selection and output=md. 25 incidents on the status feed from July to 1 October 2026, including an outage across all APIs on 10 September.

Linkup

1. On 429, check the credit balance before backing off. The same code means out of credit
2. Pass reasoningDepth: "S" to research unless you need more. The MCP default is L at $1.50
3. Start with depth=fast and outputType=searchResults. Deep costs $0.05, ten times as much
4. Send the key as an Authorization: Bearer header, not ?apiKey= or a command-line argument
5. Poll linkup-get-research with the task id. Research runs take minutes

SerpApi

1. Use the MCP with Authorization: Bearer, not the key-in-path URL the README leads with
2. Read serpapi://engines/<engine> before calling a new engine, since params isn't typed
3. Add json_restrictor or output=md to cut tokens, and mode: compact on the MCP
4. A 429 means either the hourly limit or an empty balance. Check the account before retrying
5. Repeat a search within the hour and the cached copy is free. Set no_cache=true only when freshness matters